6 THE YELLOW-FEVER MOSQUITO. 
than anemic or aged people. It will also feed upon birds, and it has 
been carried alive from Brazil to Europe by being fed upon canary 
birds. Instances are on record of the biting of corpses. 
TIME OF ACTIVITY. 
The popular name in the British West Indies, “ day mosquito,” is 
derived from the fact that this species is usually active and bites only 
in the daytime, although, where there is a light in the room, it may 
also bite at night. It is especially voracious early in the morning 
about sunrise and again late in the afternoon. It does not bite in the 
bright sunlight out of doors, and in fact is not in evidence in the 
open. On cloudy days it bites at all times. Antimosquito lotions for 
the skin, used in unscreened houses at night, are not so apt to be effec- 
tive against this species as against other semidomesticated species, 
such as Culea quinquefasciatus and the species of Anopheles, for the 
reason that at the time when the individual is soundest asleep, m the 
early morning hours, the lotion will largely have evaporated, and 
the yellow-fever mosquito begins to bite only when the sunlight first 
enters the room. 
LENGTH OF ‘LIFE OF ADULTS. 
Adult females have been kept alive for long periods by feeding them 
upon bananas and other fruit, upon honey, molasses, and other sweet 
substances. Beyond the fortieth day the mortality becomes great. 
They will live longer where the atmosphere is moist. Guiteras, in 
Cuba, kept five infected adults alive for 101 days and one for 154 
days. The oldest male that has been kept in captivity lived for 72 
days. The question of how long infected yellow-fever mosquitoes 
may be capable of conveying the disease has received some attention. 
Having acquired the infection from a yellow-fever sufferer they are 
dangerous after the twelfth day, and probably continue dangerous 
as long as they are capable of biting. 
INFLUENCE OF TEMPERATURE. 
The cessation of former yellow-fever epidemics in the southern 
United States on the appearance of the first cold weather in Novem- 
ber and December was due to the fact that the yellow-fever mosquito 
is killed by cold. It is, in fact, extremely sensitive to differences in 
temperature. It displays the greatest activity when the thermometer 
is in the neighborhood of 82° F. As the temperature rises or falls a 
few degrees above or below that point there is a markedly reduced 
activity. Beyond 102° F. heat is fatal. When the thermometer falls 
below 62° the mosquito becomes sluggish and will not feed. At from 
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